Various types of processing streams for segregating waste into discrete factions are known in the prior art. However, what is needed is a method for post-consumer waste segregation, comminution, and creation of a cementitious aggregate material that enables more complete recovery of zorba from commingled metallic and non-metallic waste while enabling creation of a cementitious aggregate having utility as a substitute for traditional concrete aggregates used in load bearing construction.
The present method for post-consumer waste segregation, comminution, and creation of a cementitious aggregate includes addition of silica to a processing stream of comminuted, commingled waste, whereby action of heat effects mechanical bonding of silica particles to the surface of plastic waste particles to create a cementitious aggregate as set forth in U.S. Pat. No. 6,488,766, which reference is included in its entirety herein by reference. This cementitious aggregate enables use of post-consumer plastics for construction and other purposes as a substitute to traditional concrete aggregates.
Addition of silica to the processing stream further enables increased efficiency in separation of zorba from plastic waste. Zorba is deflectable by action of eddy currents and a moving magnetic field applied to the processing stream. In the present state of the art, however, where addition of silica to the processing stream is not employed, plastic waste particles are seen to deflect alongside zorba, due to static cling and/or other electric interaction with conductors, whereby complete separation of zorba from plastic waste is currently impossible. However, once silica has been bonded to plastic waste particles, insulation of the plastic waste particles prevents the plastic waste particles from statically interacting with zorba particles, whereby complete separation and reclamation of zorba from plastic waste is enabled for resale.
Presently, post-consumer waste arrives for processing as commingled partially processed post-consumer waste. Such waste generally comprises 97% plastic, less than 1% ferrous waste, and approximately 2% zorba consisting mainly of beverage can aluminum (“BCA”). BCA is quite valuable, and the inability of present segregation methods to efficiently segregate BCA (and other zorba) from plastic waste which “rides along” represents a significant loss of potential value.
The present method, therefore, enables more complete recovery of zorba from plastic waste during creation of a lightweight cementitious aggregate subsequently usable as a load bearing substitute to traditional concrete aggregates. Plastics that are typically not recycled (such as those plastics identified by the number 3, i.e. poly vinyl chloride (“PVC”), for example, or the number 4, i.e. low density polyethylene, or number 7 plastics, i.e. poly carbonate (“PC”) and bisphenol A (“BPA”) are frequently interned in landfills or left elsewhere in the environment where they can cause contamination and pose health risks. The present method not only enables more efficient and profitable recovery of recyclable metallic waste for resale, said present method further enables simultaneous creation of a lightweight, load bearing construction material whereby non-recycled and disused plastics are transformable to enable further utility.